The purpose of this project is to assess the effects of acupuncture on the perceptual processess associated with human pain. Two specific studies are described and, in addition, the development of a portable dental dolorimeter is planned. The first study will test the importance of locus of stimulation and needle penetration in dental acupuncture anesthesia, using points on the hands. The second experiment will study acupuncture analgesia as generated from points on the external auditory meatus of the ear. Both of these studies will use a dental dolorimeter to create a harmless laboratory pain, and the methods associated with the theory of signal detection will be used to quantify 1) sensitivity to painful stimulation and, 2) response bias, or willingness to identify stimulation as painful. The development of a portable dental dolorimeter will provide a device which will be useful for studying pain, not only in the laboratory, but also in the clinical context. Additional experiments are proposed which will follow up the outcomes of the first studies. The objectives of these projects are to determine and to quantify the effects of acupuncture on pain and to generate hypotheses concerning the mechanisms basic to acupuncture analgesia and therapy. These investigations will provide a precise assessment of the relative importance of sensory variables and psychological factors in acupuncture analgesia.